These changes introduce a new kind of task that uses a variation of the
`task!` syntax. Existing `task!` usages create task structs that have a
`Send` bound, which requires the use of `Trusted<T>` to reference a DOM
object T inside of the task closure. The new syntax replaces the `Send`
bound with a `JSTraceable` bound, which requires explicit capture
clauses with types. This looks like:
```rust
task!(ScriptPrepare: {script: DomRoot<HTMLScriptElement>} |script| {
script.prepare(CanGc::note());
}),
```
The capture clauses must list every value that will be referenced from
the closure's environment—these values are moved into fields in the
generated task structure, which allows them to be traced by the GC as
part of a generated JSTraceable implementation. Since the closure itself
is not a `move` closure, any attempts to reference values not explicitly
captured will generate a borrow checker error since the closure requires
the `'static` lifetime.
Testing: Existing WPT tests exercise these code paths. I also attempted
to write incorrect tasks that capture references or use values not
explicitly captured, and the compiler correctly errors out.
Fixes: part of #35517
Signed-off-by: Josh Matthews <josh@joshmatthews.net>
* Migrate to 2024 edition
Signed-off-by: Simon Wülker <simon.wuelker@arcor.de>
* Allow unsafe_op_in_unsafe_fn lint
This lint warns by default in the 2024
edition, but is *way* too noisy for servo.
We might enable it in the future, but not now.
Signed-off-by: Simon Wülker <simon.wuelker@arcor.de>
* Compile using the 2024 edition
Signed-off-by: Simon Wülker <simon.wuelker@arcor.de>
---------
Signed-off-by: Simon Wülker <simon.wuelker@arcor.de>
* Use 2024 style edition
Signed-off-by: Simon Wülker <simon.wuelker@arcor.de>
* Reformat all code
Signed-off-by: Simon Wülker <simon.wuelker@arcor.de>
---------
Signed-off-by: Simon Wülker <simon.wuelker@arcor.de>
No longer hide errors while queueing tasks on the main thread. This
requires creating two types of `TaskSource`s: one for the main thread
and one that can be sent to other threads. This makes queueing a bit
more efficient on the main thread and more importantly, no longer hides
task queue errors.
Fixes#25688.
Signed-off-by: Martin Robinson <mrobinson@igalia.com>
Co-authored-by: Mukilan Thiyagarajan <mukilan@igalia.com>
This is a simplification of the internal `TaskQueue` API that moves the
`TaskManager` to the `GlobalScope` itself. In addition, the handling of
cancellers is moved to the `TaskManager` as well. This means that no
arguments other than the `task` are necessary for queueing tasks, which
makes the API a lot easier to use and cleaner.
`TaskSource` now also keeps a copy of the canceller with it, so that
they always know the proper way to cancel any tasks queued on them.
There is one complication here. The event loop `sender` for dedicated
workers is constantly changing as it is set to `None` when not handling
messages. This is because this sender keeps a handle to the main
thread's `Worker` object, preventing garbage collection while any
messages are still in flight or being handled. This change allows
setting the `sender` on the `TaskManager` to `None` to allow proper
garbabge collection.
Signed-off-by: Martin Robinson <mrobinson@igalia.com>
